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| United States Patent |
5,663,001
|
|
Textor
, et al.
|
September 2, 1997
|
Aluminum surfaces
Abstract
Articles of aluminum containing at least one unanodized surface or parts of
at least one unanodized surface which are suitable for the deposition of
layers or layer systems from the gas phase on said unanodized surfaces,
the unanodized surfaces being of a refined aluminum with a degree of
purity of equal to, or greater than, 98.3% by weight or aluminum alloys of
said aluminum with at least one of the elements from the series comprising
Si, Mg, Mn, Cu, Zn or Fe, and the surfaces have a peak-to-valley height Ra
of equal to, or less than, 1 .mu.m, and the layer or the layer system is a
reflective layer, in particular for radiations in the optical range.
| Inventors:
|
Textor; Marcus (Schaffhausen, CH);
Fuchs; Roman (Neuhausen, CH);
Gillich; Volkmar (Jestetten, DE);
Simon; Erich (Singen, DE)
|
| Assignee:
|
Alusuisse Technology & Management Ltd. (Neuhausen Am Rheinfall, CH)
|
| Appl. No.:
|
623893 |
| Filed:
|
March 25, 1996 |
Foreign Application Priority Data
| Current U.S. Class: |
428/469; 359/838; 428/457 |
| Intern'l Class: |
B32B 015/04; G02B 005/08 |
| Field of Search: |
428/687,612,457,936,336,216,469,472,697,699,701,702
359/838,884
|
References Cited
U.S. Patent Documents
| 2108604 | Feb., 1938 | Mason | 359/884.
|
| 3312535 | Apr., 1967 | Anderson | 428/687.
|
| 3372008 | Mar., 1968 | Korver | 428/687.
|
| 3499780 | Mar., 1970 | Etherington et al. | 117/35.
|
| 4301229 | Nov., 1981 | Sakaki et al. | 428/687.
|
| 4556285 | Dec., 1985 | Sugiura et al. | 428/654.
|
| 4691998 | Sep., 1987 | Sakagaito et al. | 359/217.
|
| 4826737 | May., 1989 | Yamada et al. | 428/650.
|
| 4840685 | Jun., 1989 | Nabae | 420/532.
|
| 4886713 | Dec., 1989 | Ostermann et al. | 428/687.
|
| 5017337 | May., 1991 | Nabae et al. | 420/532.
|
| 5122423 | Jun., 1992 | Hase et al. | 428/694.
|
| Foreign Patent Documents |
| 256197 | Nov., 1963 | AU | 359/838.
|
| 151985 | Aug., 1985 | EP | 359/838.
|
| 1446273 | Nov., 1968 | DE.
| |
| 57-17901 | Jan., 1982 | JP | 359/884.
|
| 60-247602 | Dec., 1985 | JP | 359/838.
|
| 1-300203 | Dec., 1989 | JP | 359/884.
|
| 2-64502 | Mar., 1990 | JP | 359/838.
|
Primary Examiner: Zimmerman; John
Attorney, Agent or Firm: Bachman & LaPointe, P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a divisional of application Ser. No. 08/351,719 filed Dec. 8, 1994,
now abandoned, which in turn is a divisional of application Ser. No.
08/044,451, filed Apr. 9, 1993, now U.S. Pat. No. 5,403,657, which in turn
is a continuation of application Ser. No. 07/812,750, filed Dec. 23, 1991,
now abandoned.
Claims
We claim:
1. Articles of aluminum which comprises at least a part of at least one
unanodized surface suitable for the deposition of at least two layers from
the gas phase thereon, wherein the unanodized surface has a peak-to-valley
height Ra of from 0.001 to 1 micron, and wherein said unanodized surface
is selected from the group consisting of (1) refined aluminum with a
degree of purity equal to or greater than 98.3% by weight aluminum and (2)
aluminum alloys with at least one of the elements from the series Si, Mg,
Mn, Cu, Zn, Fe, a ceramic adhesive layer deposited on said unanodized
surface, and at least one reflecting layer deposited on said adhesive
layer, said layers being deposited from the gas phase for the reflection
of radiation with wavelengths in the optical range, said reflecting layer
being selected from the group consisting of aluminum, silver, gold, copper
and alloys containing at least one of said elements.
2. Articles according to claim 1 wherein the surface peak-to-valley height
Ra is 0.1 to 1 micron.
3. Articles according to claim 1 wherein the surface peak-to-valley height
Ra is equal to or less than 0.1 micron.
4. Articles according to claim 1 wherein the surface peak-to-valley height
Ra is equal to or less than 0.03 micron.
5. Articles according to claim 1 wherein the unanodized surface is selected
from the group consisting of rolled foil, rolled sheets and rolled strips.
Description
BACKGROUND OF THE INVENTION
The present intention relates to articles of aluminum containing at least
one surface or parts of at least one surface which are suitable for the
deposition of layers or layer systems from the gas phase on said surfaces,
and their use.
It is known to manufacture strips in bright materials, for example refined
aluminum or AlMg alloys based on aluminum having a degree of purity of
99.8 and higher, such as, for example, 99.9%, and rolled surfaces which
produce diffuse or directed light reflection depending on application. It
is also known to polish the surfaces of such strips chemically or
electrolytically to increase the total reflection or directed reflection
and then to produce a protective layer of, for example, 1-5 .mu.m layer
thickness by anodic oxidation.
These known processes have the disadvantage that expensive bright alloys
based on refined aluminum have to be used. As a result of the anodic oxide
layer, the reflectivity of the surface, and in that connection both the
total reflection and also the directed reflection, decreases due to
absorption and light scattering, in particular in the oxide layer. This
signifies an energy loss.
Chemical treatment, and in that connection the production of the degree of
brightness in particular, is not without problems from the point of view
of environmental pollution by effluent waters and wastes.
Finally, in the normal thickness range of 1 to 3 .mu.m, the anodic oxide
layer often has troublesome interference effects, the so-called
iridescence.
The object of the present invention is to avoid said disadvantages and to
propose articles of aluminum which contain at least one surface or parts
of at least one surface which are suitable for the deposition of layers or
layer systems from the gas phase on said surfaces, and said layers or
layer systems facilitate as loss-free a reflection of energy as possible.
SUMMARY OF THE INVENTION
According to the invention, this is achieved in that the unanodized
surfaces are of a refined aluminum with a degree of purity equal to, or
greater than, 98.3% by weight or aluminum alloys of said aluminum with at
east one of the elements from the series comprising Si, Mg, Mn, Cu, Zn or
Fe, and the surfaces have a peak-to-valley height Ra of equal to, or less
than, 1 .mu.m.
Aluminum alloys containing Si are preferred, in particular, for surfaces
which are on articles which are manufactured by extruding or pressing.
DETAILED DESCRIPTION
All spatial formed bodies which have at least one free surface may find use
as articles of aluminum. Said free surface is, for example, an aluminum
with a purity of 98.3% and higher, expediently 99.0% and higher,
preferably 99.9% and higher and, in particular, 99.95% and higher. In
addition to aluminum of said purities, the surface may also represent an
alloy, preferably, for example, aluminum alloys containing 0.25 to 5% by
weight, in particular 0.5 to 2% by weight, of magnesium, or containing 0.2
to 2% by weight of manganese, or containing 0.5 to 5% by weight of
magnesium and 0.2 to 2% by weight of manganese, in particular, for
example, 1% by weight of magnesium and 0.5% by weight of manganese, or
containing 0.1 to 12% by weight, preferably 0.1 to 5% by weight, of
copper, or containing 0.5 to 5% by weight of zinc and 0.5 to 5% by weight
of magnesium, or containing 0.5 to 5% by weight of zinc, 0.5 to 5% by
weight of magnesium and 0.5 to 5% by weight of copper, or containing 0.5
to 5% by weight of iron and 0.2 to 2% by weight of manganese, in
particular, for example, 1.5% by weight of iron and 0.4% by weight of
manganese.
Examples of particularly preferred surfaces are aluminum with a purity of
99.5% and higher, 99.8% and higher, 99.85% and higher, 99.9% and higher
and 99.95% and higher, or surfaces of an aluminum alloy containing 0.5% by
weight of magnesium or containing 1% by weight of magnesium or containing
aluminum of a purity of 99% and 5 to 10 and in particular 7% weight of
magnesium and 6 to 12 and in particular 8% by weight of copper.
Examples of articles of aluminum are rolled products such s foils, strips,
panels, sheets; possibly, parts reshaped by bending, deep drawing, cold
extrusion and the like, furthermore profiled sections, girders and other
shapes of pieces. Depending on application purpose, the entire article may
be of the said aluminum or aluminum alloy, but also only subregions or
surface regions may consist thereof.
Preferred are rolled surfaces and articles which are manufactured by
rolling, i.e. for example foils, strips or sheets containing the surfaces
according to the invention. The said aluminum or the aluminum alloy may
also represent a part and at least one surface, or only a subsurface of a
composite, for example of a composite foil or laminate, or of another
substrate of any desired material such as, for example, of plastic, metal
or ceramic.
The surfaces according to the invention may be produced, for example, by
rolling or grinding. Preferred are rolled surfaces which can be produced
with smooth or structured rollers. The surfaces may be pickled, for
example, between individual, a plurality of, or all the rolling operations
(passes), this being done in particular to remove the rolling abrasion.
The pickling attacks on the surfaces can be carried out in a manner known
per se, for example acidically or alkalinely.
If structured rolled surfaces are provided for rolling, the rolled surface
can be structured, for example, in a chemical, physical or mechanical way,
for example by electron beam erosion, by laser beam erosion, by
electrolytic erosion or by sandblasting. These processes are known per se.
The unanodized surfaces according to the invention may also be subjected to
an electrolytic or electrochemical polishing process. Such polishing
processes are known per se and have hitherto been used before the hitherto
usual anodizing.
Expediently, the articles according to the invention have a surface
peak-to-valley height Ra of 0.1 to 1 .mu.m and preferably of 0.3 to 0.4
.mu.m.
These surface peak-to-valley heights result in articles with, in
particular, matt surfaces and, preferably, diffuse or directed scattering
reflection.
In another expedient embodiment, the articles have a surface peak-to-valley
height Ra equal to, or less than, 0.1 .mu.m, and preferably equal to, or
less than, 0.03 .mu.m. Preferred is a surface peak-to-valley height Ra of
0.001 .mu.m to 0.03 .mu.m, and in particular of 0.003 .mu.m to 0.03 .mu.m.
Such surface peak-to-valley heights are suitable, in particular, for the
formation of articles with highly polished surfaces and directed
reflection.
The surface peak-to-valley height Ra is defined in at least one of the DIN
Specifications 4761 to 4768.
A layer or a layer system for the reflection of energy in the form of waves
and/or particles, expediently radiation with wavelengths in the optical
range and, preferably, of visible light, in particular with wavelengths
between 400 and 750 nm, can be applied to the surfaces.
A light reflecting layer such as, for example, a layer of Al, Ag, Cu, Au or
alloys, for example containing at least one of the said elements, may for
example be provided as a layer on the surface.
Examples of layer systems are those which, starting from the surface
according to the invention, are built up from:
In some cases an adhesive layer (layer A) such as, for example, a ceramic
layer. Such layers may contain, for example, compounds of the formulae
SiO.sub.x, where x is a number from 1 to 2, or AlyOz, where y/z represents
a number from 0.2 to 1.5, or consist thereof. Preferred is an adhesive
layer containing SiO.sub.x, where x has the above meaning.
A light reflecting layer (layer B), for example a metallic layer
containing, or consisting of, for example Al, Ag, Au, Cu, or alloys, for
example containing at least one of the said elements.
A transparent protective layer (layer C), for example consisting of or
containing oxides, nitrides, fluorides, etc. of alkali metals, for example
Li, Na, K, alkaline earth metals, for example Mg, Ca, Sr, Ba, and/or
transition metals such as, for example, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y,
Zr, Nb, Mo, Te, Ru, Rh, Pd, Hf, Ta, W, Re, Os, Ir, Pt and/or lanthanides
such as, for example, La, Ce, Pr, Nd, Pm, Dy, Yb or Lu, etc. Examples are
layers containing, or consisting of, PrTi oxide and MgF.sub.2 etc.
Furthermore, two or more transparent layers (layers C, D, . . . ) having
different refractive indices may be provided to increase the reflectivity
as a consequence of partial light reflection at the phase boundary of the
layer C and layer D, or further layers.
The individual layers are typically 1 to 200 nm, preferably 1 to 100 nm
thick.
Preferred is a layer system containing a layer B and at least one layer C.
The layers may be deposited, for example, by gas- or vapor-phase deposition
in vacuo (physical vapor deposition), by thermal evaporation, by electron
beam evaporation, with or without ion support, by sputtering, in
particular by magnetron sputtering, or by chemical gas-phase deposition
(chemical vapor deposition), with or without plasma support, on the
surface according to the invention or the previous layer already applied.
The layer or the layer system on the surface according to the invention
results, in particular, in articles which have a reflection, measured as
reflection value according to DIN 67 530 with Dr. Lange RL 3, of 85 and
higher and expediently 90 and higher.
The layer or the layer system can be applied to the surface in a processing
sequence which contains the steps of degreasing and cleaning the surface,
the loading of the article containing the surface into a vacuum system,
cleaning, for example by sputtering, by discharge (glow discharge) etc.,
possibly the deposition of the adhesive layer (layer A) in the first
stage, the deposition of at least one light-reflecting layer, for example
metal layer (layer B), in a second stage, the deposition of at least one
transparent layer (layer C, possibly layer D and further layers) in a
third and possibly a fourth stage and in further stages, and the unloading
of the coated article from the vacuum.
The surfaces according to the invention which carry such a layer or such a
layer system have an excellent reflection, for example, for
electromagnetic radiation and, in particular, electromagnetic radiation in
the optical range. The optical range comprises, for example, the
infra-red, the range of visible light, the ultraviolet, the X-rays, the
.gamma.-rays etc. A preferred field of application is the range of
electromagnetic radiation and, in this connection, of visible light.
Depending on the surface, the reflection of the radiation may be directed,
diffuse or a combination thereof, as described above. Consequently, the
articles according to the invention of aluminum according to the invention
which have a layer or a layer system as described are suitable, for
example, as reflectors, such as reflectors, for example, for radiation
sources or optical instruments. Such radiation sources are, for example,
lighting fixtures or radiant heaters. The reflectors are, for example,
mirrors or inside mirrors of optical instruments, lighting fixtures or
radiant heaters.
For example, the articles according to the present invention improve the
reflection by 5 to 30%, which represents an appreciable potential for
energy saving or improvement of light yield. A complete freedom from
iridescence (interference effects in the visible wave range) is also
achieved.
The articles can be reshaped, in which process a less strongly visible
crack formation occurs than is the case in the current prior art with
anodised surfaces.
The articles and, in this connection, in particular the surfaces with the
layer or the layer system have a good protective effect with respect to
chemical, physical or mechanical degradation (for example, corrosion).
Particularly effective for this purpose is the layer C or layers C and D
and possibly further corresponding layers.
The present invention therefore also comprises the use of articles of
aluminum containing at least one surface or parts of at least one surface
according to the present invention as substrate for the deposition of a
layer or a layer system from the gas phase on said surfaces.
Preferred is the use of articles of aluminum according to the present
invention as substrate for the deposition of a reflective layer or a
reflective layer system on said surfaces.
Particularly preferred is the use of articles of aluminum according to the
present invention as substrate for the deposition of a reflective layer or
a reflective layer system for radiations in the optical range such as, for
example, heat radiation, visible light, ultraviolet, X-rays or
.gamma.-radiation etc. The reflection of visible light has particular
significance.
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